Internal combustion engine



one end thereof and this il from its piston, torque will Patented Sept. 22, 1931 UNITED sTATEs PATENT OFFICE CHARLES B. SHORT, OF DAY'I'CN, O-HIO, ABSIGNOB, BY HISNE ASSIGNMENTS, T0 PACKARD KOTOR CAR COMPANY, 0F DETROIT, MICHIGAN', A CORPORATION DI' mexican Applioationlled June 18,

This invention relates to means for reducing or eliminating the harmful effects of 'torsional vibrations in arotating shaft and is especially applicable to the crank shaft of 5,multicylinder internal combustion engines, particularly high speed engines having four or more cylinders.

Ordinarily the crank shaft of an internal combustion engine has a flywheel at only heel is of necessity placed a considerab e distance from the most distant crank pin in a multicylinder engine. Therefore when this most distant crank pin receives the power impulse e transmitted through the entire length of the crank shaft back to the heavy iywheel and since the polar inertia of the crank shaft is small compared to that of the flywheel the shaft will yield to the torsional stress a slight amount. In other words, the flywheel tends to hold that end of the crank shaft relatively stationary while the power impulse on the crank in twists the shaft. Of course the same e ect Ioccurs with all of the crank pins to some degree but the greater the distance from the crank pin to the flywheel the greater will be the twisting due to the power 4 im ulses. Since the crank shaft is made pulses set up torsional vibrations in the shaft, the natural frequency of which of course depends upon the desi of the shaft itself, according to the well a torsional pendulum. The flywheel having a substantially uniform angular velocity serves as a relatively stationary oint of support of a torsional pendulum, whilethe mass of the parts of the crank shaft, itself, and its appurtenances such as counterweights,

- actsas an oscillatory torsional pendulum having a very high frequency.

v It has been found that at certain engine speeds the power impulses on the crankI pins occur with substantially the same frequenc or with substantially one half, one thir one quarter, etc., of the natural frequency* Aof the torsional vibrations for any given crank shaft. When thls occurs the power impulse 'as well 'as the forcesof the inertia of 'ghly elastic material these twisting imown laws of INTERNAL connns'rron ENGINE 192s. semi n. 646,041.

'shaft by yieldably mounting an inertia mass,

such as a crank counterweight, upon the crank shaft;

Another object is to utilizethe inertia of the` crank counterweight as well as the 'inertia of other wheels or gears which may be driven bythe crank shaft to absorb the torsional vibrations without at the same time decreasing the frequency of these vibrations. o

Further objects and advantages of the present invention will be apparent from 'the ollowing description, reference being had to the accompanying drawings, wherein a preferred form of embodiment of the present invention is clearly shown.

In the drawings:

Fig. 1 shows in vertical section the front end of a multicylinder internal combustion engine-embodying this invention;

ig. 2 is a detail view taken on line 2 2 of Fig. 1, but showing certain parts in section, and

Flg. 3 is a viewin elevation of the engine crankshaft and ily-wheel assembly, showing the preferred, relative position ofthe inertia mass.

Similar reference characters refer to simengine may be of any conventional or' desired design and may have the cylinders eithler arranged in line or at any desired an e.

he front end 12 of the crank shaft 11 is suitably mounted in a rotating bearing sleeve 13 which in turn is rotatably mounted in a stationary front bearing 14 'suitably supported by the crank case 15. Rigidly secured to the inner end of sleeve 13, preferably by integral construction, is a suitable mass, shown in the form of an eccentrically weighted wheel 20, which preferably surrounds the crank arm and isrotatable with the crank shaft in the plane of the arm. This wheel 20 has a recess 21 therein in which the front crank arm 22 of the crank shaft ts loosely with a considerable clearance 23 at each Iside, so that the mass is movable relative to the crank shaft 11. The

crank'arm or throw 22 is yieldably held centrally of the recess 21 by yieldable damping members, such as small compressed cork inserts 25, held in suitable recesses in the wheel 20, being returned to its normal or central position after defiection therefrom by the resilience or expansibility of the yieldable members 25. Abutment members 26 of some suitable material which will not be squeezed out laterally in' the clearance space 23 may be provided to properly retain the inserts 25 at their inner ends. The inserts 25 are retained at their outer ends and adjusted in position and compressed to the desired degree by the small screw plugs 27, all as will e clearly understood from Fig. 2. It will be obvious that as the crank shaft rotates it will also rotate the wheel 20, the drive being slightly yieldable due to the compressibility of the inserts 25. The outer end of sleeve 13 has rigidly ixedthereto b any suitable means the gear wheel 30 whic y may be used to drive the cam shaft, generator, magneto, pump, or any other engine device.

Now it will bekseen that due to the yieldable drive between the crank shaft 11 and the weighted Wheel 20, the torsional vibrations of shaft 11 will not be transmitted to the gear 30 and hence the noise, wear, etc., of t e parts driven by the gear 30 will be greatly reduced.

Also, since at every torsional vibration of the crank shaft irst one of the inserts 25 is compressed and then the other, the energy of these vibrations is quickly absorbed in internal friction in the material of the inserts 25. Therefore these vibrations will be continually damped and prevented from reaching objectionable proportions. The in# serts 25 instead of being made of cork may be made of any suitable material which has the desired properties of yieldability and mechanical hysteresis, that is, it should have a considerable amount of internal friction between the molecules soathat when it -is made to yield by some force, a considerable part of the work done upon-it is absorbed by 1,824,6so l throw a similar counterweight must also be.

used for a similar but opposite crank throw to preserve the proper balance of the entire crank shaft. The inertia ofthe rotating mass of Wheel 20, together with the inertia of the gear 30 rigidly connected thereto will give a substantially constant an y lar velocity to wheel 20, regardless of t e torsional vibrations in the crank shaft 11;

While the form of embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be underfabric material may be stood that other forms might be adopted,

all coming within the scope of the claims which follow.

What I claim is as follows:

1. In an internal combustion engine and in combination with the crank shaft thereof, and a crank case having an end wall; a rotatingtorsional vibration damping member located within said crank case and having a laterally extending tubular bearing sleeve rotatably supported in a bearing carried by said end wall, and through which sleeve one end of said crank shaft extends; and. yieldable means whereby said rotating member is driven from said crank shaft.

2. In an internal'combustion engine and in combination with the crank shaft thereof, and a crank case having an end wall; a rotating torsional vibration damping member located within -said crank case and having a laterally extending tubular bearing .sleeve rotatably supported in a bearing carried by said end wall, and through whieh end of said crank shaft extends; and two sleeve onel yieldable shock absorbing members acting t in opposition to one another and through which said crank shaft and said rotating member are coupled together so asto rotate in unison.

3. In van internal combustion engine and in combinationy with the crank shaft thereof, and a crankcase having an end wall; a ro*-v tating torsional vibration damping member'.

located within said crank case and having a laterally, extending tubularv bearing sleeve rotatably supported in a bearing'jc'arriedby' said end wall, andgthroughywhi'ch sleeve Ione .lf end of said crankshaftextends'f;yieldable 130.

means whereby said-.rotating .'member Ais driven from said crank shaft; and a driving gear fastened to the outer end of said sleeve so as to be driven thereby.

4. In an internal combustion engine and in combination with the crank shaft thereof, and a crank case having an end wall; a rotating torsional vibration damping member located within said crank case and having a recess adapted to receive an arm or throw of said crank shaft, and also two other recesses arranged in alignment and at right angles'to said first mentioned recess; and two yieldable shock absorbing members arranged within said last mentioned recesses and actin in opposition to another upon opposite sides of said crank arm.

5. In an internal combustion engine and in combination with the crank shaft thereof, and a crank case having an end wall; a rotating torsional vibration damping member located within said crank-case and having a laterally extending tubular bearing sleeve rotatably supported in a bearing carried by said end wall, and through which sleeve one end of said crank shaft extends; and two yieldable shock absorbing members carried by said rotating member and actin in opposition to one another upon opposlte sides of an arm or throw of said crank shaft.

6. In an internal combustion engine and in combination with the crank shaft thereof, and a crank case having an end wall; a tubular sleeve rotatably supported in a bearing carried by said end wall, and through which sleeve one end of said crank shaft extends; means including a yieldable member' whereby the inner end of said tubular sleeve is driven from said crank shaft; a driving gear fastened to the outer end of said sleeve so as to bedriven thereby; and a torsional vibration damping member carried by and rotatable with Ysaid sleeve.

7. Means for damping torsional vibrations in a shaft including, a rotating mass driven by said 'shaft in either direction through yieldable shock absorbing material,

said rotating mass being so arranged asto act as` a balance weight for said rotating shaft.

S In an internal combustion engine havling a crank shaft, in combination, a counterweight yieldingly secured to said shaft to permit a slight relative displacement therewith, andim rfectly elastic means to `ordinarily retam. said counterweight in its correct relative osition upon said shaft whereby torsionall vibrations in said shaft are eliminated.A

9. In an internal combustion engine a crank shaft adapted to have a flywheel at one end thereof, in combination, a-counterweight yieldingly secured to saidshaft substantially opposite the crank throw most distant from said flywheel to permit a slight .relative displacement therewith, and imperfectly elastic means to ordinarily retain said counterweight in its correct relative osition upon said shaft whereby torsional vilirations in said shaft are eliminated.

10. In an internal combustion engine having a crankshaft adapted to have a fly-wheel at one end thereof, 1n combination, a counterweight, and means whereby said counterdriven by said shaft in either direction,

through non-metallic ener absorbing material, said material transmltting the driving force by being compressed.

12.. lIn a crank shaft having a crank arm,

an inertia mass rotatable with the crank shaft in the plane of the arm and movable relatively thereto in response to inertia forces.

13. In a crank shaft having a crank arm an inertia mass on the shaft adjacent said arm and movable relatively thereto, and resilient means directly connecting said mass and arm to resist said relative movement.

14. In a crank shaft havin a crank arm, an inertia 'mass movable reitively to the shaft in the plane of said arm and resilient means between the mass and said arm opposing relative movement in either direction.

15. In a crank shaft, a mass means to movably mount the mass onsaid shaft for rotation about an axis fixed in relation to the shaft, and resilient non-metallic energy absorbing means between said shaft and said mass opposing said movement.

16. In a crank shaft having a crank throw an inertia membermovably mounted on sa1d shaft adjacent said throw to rotate about an axis fixed in relation to the shaft, and yieldable means directly conneetin \said member' to said throw.

17. n a crank shaft having a crank arm, an inertiaV mass mounted on said' shaft in the lane of said arm and movable relativelyjt ereto, and resilient means betweenthe crank arml and the mass to limit said relative movement.

18. In a crank shaft having a crank arm, an inertia mass mounted on said shaft in the plane of said arm and-movable relativey thereto, and means to relative movement.

19. In a crank shaft having a crankthrow,

a mass movably mounted adjacent said throw,-

and opposed means yieldably and directl connecting the mass to said throw. 20. In a crank shaft having a crank throw, an inertia mass movably mounted on said shaft adjacent said throw,` and yieldable means abutting said mass vand Athrow yieldably oppose said for opposing relative movement in either direction of rotation.

21. In a crank shaft having a crank arm, a mass movably mounted in the plane of said arm, and adjustable yielding means between said arm andsaid mass opposing relative movement therebetween.

22. In a crank shaft having a crank arm, an inertia mass in the plane of said arm and movable relatively thereto, yieldable means between said arm and said mass, and means toA adjust the resistance of said yieldable means.

23.- In a crank shaft having a 'crank arm, an inertia mass in the plane of said arm and movable relatively thereto, yieldable means carried by said mass to resist said 'relative movement, and means on said mass `to adjust the resistance of said yieldable signature.

. CHARLES R. SHORT.

24. In a crank shaft having a crank arm-, iy

, torsional vibrations of the shaft.

25. The combination with a crank shaft of a counter-weight therefor, and means associated with the counter-wei ht to damp torsional vibration in said sha t.

26. The combination with a crankshaft of `a vibration damper including an inertia member associated with friction damping means, said inertia member being disposed .to counter-balance a crank of said crank shaft.

In an internal combustion engine, the combination of a vibration damper and a counter-weight, said counter-weight forming the inertia member of said vibration damper. v

V28. In an internal vcombustion engine, a crank shaft, and ,a combined vibration damper and counter-weight for said crank shaft. j

29. In an internal combustion en 'ne and in combination with the crank sha t there` of, an inertia' member movable relative to said crank shaft, and yieldable means of energy absorbing material including nubber connected between .the crank shaft and the inertia member to distort in response to said relative movement. l p

30. A vibration damper for crank shafts comprising an inertia member movable relative to the shaft, and a member of energy absorbingmaterial including rubber eformable inresponse to said relative movement.

31. vibration damper for crank shafts comprising an inertia member movable re1- ative to the shaft, and yieldable means connected between said shaft and inertia member and including rubber, adapted to absorb energy upon deformation in response to said movement. 

